1. The Field of the Invention
The present invention relates generally to methods and systems for determining the authenticity of objects. More particularly, the present invention is related to methods and systems for verifying the authenticity of an item by scanning for a security feature having defined spectral characteristics and analyzing the results.
2. The Relevant Technology
In modern society, various conventional methods are utilized to trade goods and services. However, various individuals or entities wish to circumvent such methods by producing counterfeit goods or currency. In particular, counterfeiting of items such as monetary currency, banknotes, and credit cards is a continual problem. The production of such items is constantly increasing and counterfeiters are becoming more sophisticated, particularly with the recent improvements in technologies such as color printing and copying. In light of this, individuals and business entities desire improved ways to verify the authenticity of goods exchanged and/or currency received. Accordingly, the methods used to prevent counterfeiting through detection of counterfeit articles or objects must increase in sophistication.
Prior verification methods include detection of fluorescent and magnetic materials, pattern or image recognition, and detection of conductive elements. However, computers can duplicate such patterns or images, and fluorescent, magnetic and conductive materials are readily available to counterfeiters.
Conventional methods used to scan currency and other security items to verify their authenticity are described, for example, in U.S. Pat. Nos. 5,915,518 and 5,918,960 to Hopwood et al. The methods described in the Hopwood patents utilize ultraviolet (UV) light sources to detect counterfeit currency or objects. Generally, the tested object is illuminated by UV light and the resultant quantity of reflected UV light is measured by way of two or more photocells. The quantity of UV light reflected from the object is compared against the level of reflected UV light from a reference object. If the reflectance levels are congruent then the tested object is deemed authentic.
The methods in the Hopwood patents are based on the principle that genuine monetary notes are generally made from a specific formulation of unbleached paper, whereas counterfeit notes are generally made from bleached paper. Differentiation between bleached and unbleached paper can be made by viewing the paper under a source of UV radiation. The process of detection can be automated by placing the suspect documents on a scanning stage and utilizing optical detectors and a data analyzing device, with associated data processing circuitry, to measure and compare the detected levels of UV light reflected from the tested document.
Unfortunately, there are many problems with UV reflection and fluorescence detection systems that result in inaccurate comparisons and invalidation of genuine banknotes. For example, if the suspect object or item has been washed, the object can pick up chemicals that fluoresce and may therefore appear to be counterfeit. As a result, each wrongly detected item must, therefore, be hand verified to prevent destruction of a genuine object.
Conventional methods to detect counterfeit objects by using magnetic detection of items that have been embossed or imprinted with magnetic inks are less desirable, since magnetic inks are available to counterfeiters and can be easily applied to counterfeit objects. Other conventional methods using verification of images or patterns on an object can be fooled by counterfeit currency made with color photocopiers or color printers, thereby reducing their anti-counterfeiting effectiveness.
Verification methods that utilize the properties of magnetic detection to detect the electrical resistance of items that have been imprinted with certain transparent conductive compounds are relatively complicated. Such methods require specialized equipment which is not easily available, maintainable, or convenient to operate, particularly for retail establishments or banks that wish to quickly verify the authenticity of an item.
Various items such as banknotes, currency, and credit cards have more recently been imprinted or embossed with optical interference devices such as optically variable inks or foils in order to prevent counterfeiting attempts. Optical interference devices react to light in a unique manner not easily simulated by other materials. For example, the optically variable inks and foils exhibit a color shift or flop that varies with the viewing angle. While these optical interference devices have been effective in deterring counterfeiting, there is still a need for an accurate measuring method to verify that an item is imprinted with an authentic optical interference device, since prior conventional methods are not effective in verifying the presence of optical interference devices.